Galvanometer with float supported spindle



Dec. 27, 1949 c. A. DE GIERS ET AL 2,492,273

GALVANOMETER WITH FLOAT SUPPORTED SPINDLE Filed July 20, 1946 2 Shets-Sheet 1 Arrow Patented Dec. 27, 1949 umrso QFFIIQE GAL-VANOMETER: WITH FLOAT SUPPORTED- srmnnn ClarencaA. do Giers,

S ndberg, Que ns Forest: Hills-, anifiolf. A; Village,.N. Y., assignors to. The Liquidometer. Corporatiom. Long lslarul.-

City,1N.-' Y a; corporationloffDelaware ApplicationiJuly 20', 1946;. Serial No. 685112;.

ing system of an indicator.v on. its bearings, thus.

rendering the instrument. essentially free from the effects of. friction. This .is accomplishedby supporting thesysternona float operating in a bath of liquid in such-a way that. substantially the entireweight of; the-.moving. system issupportedby thefloatinstead of .bythe bearings.

Another object of. this invention isto.-provide1 an indicator. having improveddamping characteristics and'one which isnotafEected-by mois ture.

Other and: further objects of this, invention. will be more. apparent-after, anexaminationof;

the specification in. conjunction with the accompanying: drawings. It is understood, however, that the drawings are for the purpose of illustration only and are. not. intended to define the limits of the invention.

In the drawings:

Fig. l is a general view substantially in perspective of an indicating instrument showing the principle, of the invention;

Fig. 2 is aside view; .partlyin-section;,of" the instrument shown inFig, 1;

Fig. 3 is: a. schematic wiring diagram. illustrating a typical. application of: the invention; and

Fig. 4 is a fragmentary detail view in perspective and on a larger scale illustrating the mounting for the adjustable balancing weights shown in Figs. 1 and 2.

In the drawings, the indicator as an entirety is designated Hi. It comprises a casing or housing member II, which may be molded from glass or other transparent material, closed by a transparent cover l2. This cover may be sealed in place. Instead of making the entire casing or housing of transparent materials it may, of course, be composed of other materials with only sols-rims. (014711-95) ings.

2; a. transparentv portion through. which the internal. mechanism maybe viewed.

Within the housingis asupport or frame l3. having a bottom portion l4 resting, on or secured.

. to thebottompf. thehousing member I] and a forwardly, extending, upper. portion I5 which is constructed to provide a pointer. lB',Ithe purpose.

of.: whichwill be madeclear later on. The portions. l4.- and I5. of. the frame, are provided with.

conical recesses I1. and l8 constituting bearingstoreceive thepointedends of ashaft l9.

Attached to the underside ofthe portion I?) of the frame l3-andithe pointer. |6;.are.three. brackets 22, only twoof, which appea in. the draw- Each. of. the; three.- brackets supports a disc-likecoil 23,. 24,, 25;

' Secured to theshaft. H! are two permanent magnets 26 and 21 which are magnetized across. their. diameters and..so..arranged relatively that the;positivel polerof one is opposite the negative pole of theother.

The three coils. 23, 24, 25, the .magnets .26 and 21, and a wayotcausinglthem to functionin an indicator are fully describedin. application SeriallNo. 633,800 filedDecember 8, 1945 by Clar-.

ence A-. 'de,Giers and=.Soren.B. Osterlund which is now Patent No. 2,450,331,,issued September. 28, 1948. A. similar arrangementforcausing the coils and magnetstofunction will bereferred to briefly later on. It. is sufficient. at this. point to. say thatthemagnets andthe coils cooperate to turn the. shaft lslfrom a zero orstarting position to any angular position and from one angulanposition to another within the indicat-' ing range of the. I particular. instrument.

Securedtotheshaft. i9 is an element 3| which. is usually referred to hereinasa float. Preferably it. is made .of thin flightmetal. and includes a. hollow- .bowlshaped portion. 32 which is her-- metically sealed,..'as' by a. cover. 33,- the interiorcontainingair. atsatmospheric pressure or possible partially evacuated before sealing.

Near itsllower end the shaft. IBcarries a spider.

34; the three..arms .35lof which. arethreaded tocooperate with weights 36'. These weights may be adjusted along the arms 35 to attain a fine balance of the shaft I9 in its bearings and weights of different sizes may be used to adjust the buoyancy of the float 3| to the particular fluid used in connection with the float. Preferably, the fluid is an oil which substantially fills the housing II, the level being indicated'at 31. As will be seen, both the stationary parts and the movable parts of the apparatus are all submerged in and protected by the oil. The

fact that the weights 3b and their supporting spider arms 35 move through the oil when the shaft 19 turns causes them to serve efficiently in damping out undesired movements of the shaft 19 and the parts attached thereto.

The bowl shaped portion 32 of the float carries scale 33 cooperating with the pointer l6. As the shaft 19 is turned under the influence of the stationary coils and the permanent magnets and 21 attached to the shaft, the scale indicia It is apparent that in any of me embodiments described or referred to the invention affords an economical and highly satisfactory way of obtaining accurate indication because all friction between the moving elements and the stationary elements is substantially eliminated.

While the invention has been explained by describing mainly a specific embodiment, it is not the desire to be limited by anything set forth in opposite the pointer will indicate the value which j' has been impressed by the coils on the moving part of the system. The indicia of thescale 38 may be marked directly on the float, although I for purposes of shielding, it is preferable to mark 8 them on a band of soft iron secured around the float. If such a band is employed, the instrument will be free from errors due to hysteresis because of the fact that there will be no relative movement between the shield and the magnetic elements. The fact that the magnetic elements are supported by the buoyancy of the fluid, permits larger masses to be used thus affording greater freedom of design.

The instrument so far described may be connected to and indicate the position of a toroidal transmitter comprising a resistance element 39 (Fig. 3). The end 49 of coil 23 is connected to tap H of the resistance element by a wire 42. The end 33 of the coil 24 is connected to tap Q4 of the transmitter by a line wire 45. Similarly the end 46 of the third coil 25 is connected to tap 48 of the transmitter 39 by a line wire iii. The other ends of the coils 23, '24 and 25 are connected together by a wire 52. Wiper arms 53 and 54 are mounted to extend diametrically opposite to each other and are connected to a source of power supply 55.

In operation, as the wipers 53 and 54 move around the resistance element 39 of the toroidal transmitter the voltage distribution across coils 23, 24 and 25 will vary. The resultant field of the three coils will cooperate with the magnets 25 and 2! to turn the movable portion of the instrument so that the pointer H5, in cooperation with the scale 38, will indicate the position of the wipers 53 and 54. The wipers may be moved by a float or other system which is controlled by the rise and fall of the liquid in a tank, although obviously the wipers may be adjusted by any sort of a medium which can be measured by an indicating instrument of the character herein described.

It is obvious that while the invention has been shown and described as embodied in an instrument having a vertical shaft, the shaft may actually be made to operate in any desired position. The invention may also be made applicable to a moving coil type of meter and to any feasible circuit combination. In fact the invention is capable of use generally in instruments of the character described regardless of the particular means employed'for imparting movement to the movable systems or parts thereof.

the foregoing specification or in the drawings except to the extent indicated by the claims which follow.

What is claimed is:

1. A device. of the character described comprising a liquid filled container having at least one transparent wall portion, a supporting frame in the container below the level of the liquid, a rotatable shaft mounted in bearings on said frame, means for turning said shaft to various angular positions, a float secured to said shaft, a plurality of arms rigid with and extending radially from the shaft, weights on said arms adjustable individually to balance the shaft in its bearings, said weights being selected as to size to adjust the buoyancy of the float, an indicator scale on the float visible through the transparent portion of the container wall and an indicator pointer on the frame cooperating with said scale.

2. In an indicating instrument of the character described, a housing filled with a fluid and having at least one transparent wall, a stationary assembly within said housing comprising a plurality of coils, a rotatable assembly within said housing comprising a rotor shaft, two transversely magnetized rotor magnets fixed on said shaft and having opposite polarities and arranged one on either side of said coils in a direction axially of said shaft cooperating with said coils, means secured to said shaft for buoying the rotatable assembly in the fluid, an indicating pointer rigid with the stationary assembly, and an indicator scale on themoving assembly cooperating with the pointer, said pointer and said scales being visible through said transparent wall of the housing, and said indicator scale being marked on a strip of soft iron secured to the movable assembly adjacent to the position of said rotor magnets and said coils.

CLARENCE A. DE GIERS. ROLF A. F. SANDBERG.

REFERENCES CITED The following references are of record in the file of this patent:

De Giers et a1 Sept. 28, 1948 

